Hi Aleksei,

the "returned through security inspection" note on your package doesn't necessarily mean your specific item was banned or dangerous. It most likely means your package was part of a larger group shipment that was rejected by security at the airport for containing an item that couldn't be shipped by air.

Understanding the "Security Inspection Return"

Here's what likely happened to your package, step-by-step:

Your package passed the first check: It successfully cleared the initial export customs in Dongguan (东莞) and arrived at the Guangzhou International Exchange Bureau on March 22nd. At this point, it was sealed into a large mail bag (a process called "direct seal" or "直封").

The entire bag was rejected at the airport: This sealed bag, containing your package and many others, was sent to the airport for security screening before being loaded onto an airplane. During this X-ray inspection, the security officers found an item in one of the packages within the bag that is prohibited from air transport. As a result, the entire bag was rejected and sent back.

Your package was flagged: When the bag was opened back at the exchange center, all packages inside were checked. Yours, along with others, was identified as part of that rejected bag, hence the "returned" status on your tracking.

The timing of your tracking events supports this. The fact that your package was initially processed for export on March 22nd, but then showed the "returned" status in Guangzhou on April 2nd, is a classic pattern for a group security rejection.

Common Reasons for a Bag Being Rejected
The security inspection at the airport is for flight safety. A bag can be rejected for many reasons, some of which are not obvious. Common causes include:

Prohibited items: Items like lighters, power banks, perfumes, aerosols, flammable liquids, or batteries are strictly forbidden on passenger aircraft.

Packaging issues: Even if an item is generally allowed, if it is not packaged correctly (e.g., a liquid in a non-leakproof container), it can be flagged.

Unrelated items: As mentioned earlier, it just takes one problematic package in the bag to cause a rejection for everyone else in that bag. Your neighbor's power bank could be the reason your books are being returned.

What Should You Do Next?
You need to contact the selller to reflect the problem and require the seller to give you a solution in time.